There exist in the marketplace today a number of different hook-fastener media to be described below. It is my belief that each of these existing hook-fasteners suffers from one or more shortcomings which hamper their utility and utilization.
1. Woven hook-fastener medium:
The original hook-fastener medium is fabricated by a needle loom, and it is currently made as a tape approximately one to four inches wide having a selvage along each margin of the tape, the tape has a woven substrate with an oriented monofilament woven by the loom into the substrate while the substrate itself is being woven. This monofilament is woven with periodic protruding loops which are thereafter heat set and subsequently picked up in the loom or in a secondary machine by small needles. Associated with these small needles are small cutters which serve to cut each loop at a cutting position which is oriented between 3 o'clock and 4 o'clock. Each cut loop thus forms a protruding hook, but there remains a stub of each cut loop standing closely adjacent to the tip of the hook.
One of the shortcomings of this woven hook-fastener medium is that the loops are not always cut, and the stubs which remain near the cut tips of the hooks interfere with and prevent the desired hooking engagement with an opposed loop medium. Consequently, a significant number of the hooks do not engage into the loops or apertures. In other words, the hooking efficiency is reduced by the presence of the stubs and uncut loops.
A second shortcoming of the woven hook-fastener medium results from the fact that any given needle loom can produce only one size of cut hooks. The cut hooks are always formed of monofilaments of the same characteristics and same denier, and the tape is always of the same width. In other words, there is no possibility of adjusting the loom for producing different widths of tapes or different sizes of cut hooks or different spaces between the hooks or different characteristics of the hooks, such as different resilience or different hooking strengths. In summary, the loom can slowly produce only one product.
A third shortcoming of this woven hook-fastener medium results from the fact that the woven-in monofilaments which form the cut hooks must be bonded into the woven substrate for preventing their extraction from the substrate whenever the hook medium is forcefully separated from a loop medium by pulling them apart. The lower surface of the woven substrate is coated with a tacky bonding agent. Then, this bonding agent is cured for permanently anchoring the cut hooks into the woven substrate. This bonding agent causes the lower surface of the woven substrate to have a glazed appearance. The woven tape as a whole has an unattractive stiffness and has an unattractive "feel" as compared with ordinary woven fabric tapes.
The fourth and most important shortcoming of the woven hook-fastener medium is its relatively great expense, caused by the slow speed at which the tape can be woven in a needle loom. Such needle looms are very complex, with many intricate small parts. Increasing the width of the woven tape slows the lineal production speed, because increasing the width of the loom inherently slows down its lineal production speed, thus increasing the cost per unit length. The relatively high cost of the woven hook-fastener medium has restricted and limited its commercial applications, for example, to closures for expensive clothing and sporting shoes, closures for watch bands, and the like.
2. Molded hook-fastener media:
During the time period from early 1961 to mid 1972, the present inventor was previously active in this hook and loop fastener field, as shown by U.S. Pat. Nos.
______________________________________ 3,147,527 3,586,060 3,708,382 3,196,490 3,594,863 3,715,415 3,546,754 3,594,865 3,732,604 3,550,223 3,595,059 3,735,468 3,550,837 3,629,032 3,781,398 3,562,044 3,665,584 3,801,245 3,562,770 3,695,976 ______________________________________
In order to increase the production speed for making hook-fastener media beyond the speed which is possible for the woven-type as described under section 1 above, the present inventor conceived and developed a molded hook-fastener. The hooks are molded of plastic material integral with a substrate layer. Thus, the lineal production speed of the substrate with the hooks protruding can be considerably increased, as compared with the operation of the slow-speed, intricate needle loom.
Some molding machines of the present inventor were subsequently modified to produce a double-hook having two hook-shaped heads on each single shank. These hook-shaped heads are located on opposite sides of the shank, i.e. they are angularly spaced 180.degree. about the longitudinal axis of the shank, similar to the double-hook on the shank of an anchor from an old sailing vessel. Such a molded double-hook-fastener medium has a strong gripping effect on the loop medium. It is difficult to separate them. If sufficient pulling, peeling force is applied to separate the molded double-hook-fastener from the loop medium, many of the loops become broken or torn apart. Thus, the molded double-hook-fastener medium is best suited to permanent industrial-type attachments.
One shortcoming of these molded hook-fastener media results from the fact that the hooks must be molded of a relatively stiff plastic material in order for them to have sufficient strength to provide the desired hook-like gripping engagement with the loop medium. Since the hooks are molded integral with the substrate tape, this tape itself has a relatively stiff rigidity, which makes the molded hook-fastener media unsuitable or unattractive for use in visible locations or as closures on clothing. Thus, the molded hook-fastener media, whether single-hook or double-hook, are limited to industrial-type uses in hidden locations, for example, to secure floor pads in place in vehicles.
Another shortcoming of the molded hook-fastener media is the expense of replacing the molding plates of the molding machine to change the size or characteristics of the hooks. Also, a relatively narrow tape is produced, and its width cannot be adjusted, so it produces only one product, but it is very considerably faster than the original needle loom.
3. Molded mushroom-hook-fastener medium:
A variation of the molded single-hook or double-hook fastener media is to form a mushroom-shaped head on the protruding shank of the hook. Such mushroom heads can be molded onto each shank in the first instance. Alternatively, the outer end of each shank can be "upset" by heat and pressure in order to forge the mushroom heads on the shanks.
Such a molded mushroom-hook-fastener medium has a strong gripping effect on the loop medium, and they are difficult to separate. When sufficient pulling, peeling force is applied to separate these fasteners, numbers of the mushroom heads become snapped off of their shanks or the shanks are snapped off at their roots. Therefore, mushroom fasteners are best suited to permanent industrial-type attachments.
In summary, all three molded-type hook fasteners (single-hook, double-hook, or mushroom head) suffer from the disadvantage that the substrate must be molded from the same material as the hooks. It is not possible, up to the present time, to make the substrate of attractive, desirable, compliant material different from the stiff, plastic material used to mold the hooks.